Large Banded Agate In Silver

I love the simplicity and elegance of this pin. It demands your attention without being too showy. It is over 1 1/4 inches across and the agate is 31.5mm across. It is nice and high domed. The back is marked with a hallmark with numbers denoting the grade of silver. It is either 800 or 900, half of it is rubbed off so it is not possible to tell. There is a locking clasp and a swing bale so it is possible to wear this as a pendant. C/. 1920 and continental in origin.